Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxytocin (OT) and vasopressin (AVP) mediate their biological actions by acting on four known receptors: The OT (uterine) and the AVP V(1a) (vasopressor), V(1b) (pituitary), V(2) (renal) receptors and a fifth putative AVP V(1c)? (vasodilating) receptor. This presentation will summarize some highlights of the recent progress, in the design and synthesis of selective peptide agonists, antagonists, radioiodinated ligands, fluorescent ligands and bivalent ligands for these receptors. Here we present published and unpublished pharmacological data on the most widely used agonists, antagonists and labelled ligands. The pharmacological properties of promising new selective OT antagonists and V(1b) agonists are also presented. This review should serve as a useful guide for the selection of the most appropriate ligand for a given study. The current status of non-peptide OT and AVP antagonists and agonists is also summarized. The relative merits of peptide and non-peptide AVP and OT agonists and antagonists as: (1) research tools and (2) therapeutic agents will be evaluated. Many of the receptor selective peptide agonists and antagonists from this and other laboratories are far more widely used as pharmacological tools for studies on the peripheral and central effects of OT and AVP than their non-peptide counterparts. In addition to OT and to a lesser extent AVP (pitressin), a number of OT and AVP analogues; such as carbetocin (OT agonist) dDAVP (desmopressin, V(2) agonist), terlipressin (V(1a) agonist), felypressin (V(1a) agonist) and atosiban (Tractocile OT antagonist) are also in clinical use. Despite much early promise, no non-peptide V(1a) or OT antagonists are currently in clinical trials. While a number of orally active non-peptide V(2) antagonists (Vaptans); notably, Tolvaptan, Lixivaptan and Satavaptan, are currently in Phase III clinical trials; to date, only the mixed V(2)/V(1a), antagonist Conivaptan (Vaprisol), has been approved by the US FDA for clinical use (by i.v. administration), for the treatment of euvolemic and hypervolemic hyponatremia in hospitalized patients. Promising new non-peptide V(1b) and OT antagonists, as well as non-peptide V(2) and OT agonists are now in pre-clinical development.
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PMID:Peptide and non-peptide agonists and antagonists for the vasopressin and oxytocin V1a, V1b, V2 and OT receptors: research tools and potential therapeutic agents. 1865 3

Acute heart failure syndromes are a common cause of emergency department visits and hospitalization in North America and Europe. Although in-hospital mortality is relatively low, the postdischarge mortality and rehospitalization rates can be as high as 10-15 and 30%, respectively, within 60-90 days following discharge. It appears that the main reason for admission and readmission for heart failure is related to congestion manifested by dyspnea, jugular venous distension and edema. Often, congestion is associated with dilutional hyponatremia that is difficult to treat. Hyponatremia is an important predictor of increased mortality and the available therapies to treat congestion and/or hyponatremia are often ineffective and/or unsafe. Accordingly, there is an unmet need to develop a new agent that effectively relieves congestion due to high filling pressure without worsening renal function and improving or normalizing serum sodium in hyponatremic patients. This paper provides an overview of a new compound, tolvaptan, an oral selective V(2)-vasopressin antagonist in light of the recently published Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial. The biochemical and pharmacological properties are discussed in conjunction with its clinical efficacy and safety, exploring the potential role of tolvaptan in the management of acute heart failure syndromes presenting with or without hyponatremia.
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PMID:EVEREST study: Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan. 1901 85

Antidiuretic hormone, also known as arginine vasopressin, is a hormone with a multitude of physiologic activities including the control of urinary free water excretion. Antidiuretic hormone also plays a role in vasoconstriction and has 3 receptors that have been identified. Vasopressin analogs and antagonists have been extensively studied in animal models as well as in humans. Because heart failure is associated with a state of water retention, several vasopressin antagonists have been evaluated for their potential aquaretic effect. Diuretics remain the mainstay of treatment in acute and chronic volume overload but are not shown to improve survival. In fact, they are associated with numerous side effects including hypotension, electrolyte abnormalities, worsening renal function, and activation of renin-angiotensin-aldosternone system. Tolvaptan, conivaptan, and lixivaptan are some of the vasopressin antagonists that have been studied in heart failure. The results were initially encouraging with alleviation of symptoms and effective aquaresis without worsening of hyponatremia or renal function, but yet failed to show any effect on mortality in heart failure. With an increasing number of more selective orally active vasopressin antagonists, further studies are underway to establish the role of "Vaptans" in the treatment of heart failure and other disease states with volume overload and hyponatremia.
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PMID:Vasopressin and vasopressin receptor antagonists in heart failure. 1909 65

Tolvaptan is a selective arginine vasopressin (AVP) V(2) receptor blocker used to induce free water diuresis in the treatment of euvolemic or hypervolemic hyponatremia. Currently the orally active medication is in the final stages prior to approval by the FDA for outpatient therapy. It appears to be safe and effective at promoting aquaresis and raising serum sodium levels in both short- and long-term studies. Tolvaptan is also effective for treatment of congestive heart failure (CHF) exacerbation, but whether there are long standing beneficial effects on CHF is still controversial. Prolonged use of tolvaptan leads to increased endogenous levels of AVP and perhaps over-stimulation of V(1A) receptors. Theoretically this activation could lead to increased afterload and cardiac myocyte fibrosis, causing progression of CHF. However, after 52 weeks of tolvaptan therapy there was no worsening of left ventricular dilatation. In addition, tolvaptan is metabolized by the CYP3A4 system; thus physicians should be aware of the potential for increased interactions with other medications. Tolvaptan is a breakthrough in the therapy of hyponatremia as it directly combats elevated AVP levels associated with the syndrome of inappropriate secretion of antidiuretic hormone, congestive heart failure, and cirrhosis of the liver.
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PMID:Tolvaptan and its potential in the treatment of hyponatremia. 1933 22

Tolvaptan is an orally administered, nonpeptide, selective arginine vasopressin V(2) receptor antagonist that increases free water clearance, thereby correcting low serum sodium levels. SALT-1 and -2, two identical, randomized, double-blind, placebo-controlled, multicentre trials, included patients with hypervolaemic or euvolaemic hyponatraemia (serum sodium <135 mmol/L) associated with heart failure, cirrhosis or the syndrome of inappropriate antidiuretic hormone secretion. In both trials, patients receiving (in addition to standard medical treatment) tolvaptan 15-60 mg once daily (titrated according to response) for up to 30 days (n = 95 and 118) experienced significantly greater improvements than those receiving placebo (n = 89 and 114) for the co-primary endpoints of the change in average daily area under the curve for the serum sodium level from baseline to day 4 and from baseline to day 30. This beneficial effect of tolvaptan on serum sodium levels in SALT-1 and -2 was observed in patients with mild (serum sodium <135 mmol/L) and in those with marked (serum sodium <130 mmol/L) hyponatraemia at baseline. Tolvaptan was also superior to placebo in increasing serum sodium levels from baseline to day 7 in a subgroup of 323 patients with hyponatraemia (serum sodium <134 mmol/L) in the randomized, double-blind, multicentre EVEREST trials, which included patients who were hospitalized for worsening heart failure. Tolvaptan was generally well tolerated in clinical trials. The most frequently reported adverse events were thirst and dry mouth, which result from the pharmacodynamic effects of the drug.
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PMID:Tolvaptan. 2020 86

The effects of stable chronic hyponatremia on the central nervous system are largely unknown, clinically, or in experimental animals. The aim of this study was to identify and characterize these effects in rats. Tolvaptan, a vasopressin V(2) receptor antagonist, was used to correct hyponatremia and determine any potential benefits of such treatment in this condition. Stable chronic hyponatremia was induced by combination of the continuous vasopressin V(2) receptor stimulation and liquid food intake. The hyponatremic rats did not exhibit significant changes in general symptoms or neurological functions assessed by modified Irwin's method, or in motor function assessed by the rotarod test. In passive avoidance test, however, rats with moderate and severe hyponatremia had significantly reduced step-through latency, indicating impairment in memory. This reduced step-through latency was improved by the treatment of tolvaptan (0.25-8 mg/kg daily doses), a vasopressin V(2) receptor antagonist. This improvement is associated with normalization of plasma sodium concentrations in hyponatremic rats. In conclusion, these data suggest that chronic hyponatremia may impair memory, and treatments that normalize sodium level, such as vasopressin V(2) receptor antagonists, may be beneficial to patients with hyponatremia.
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PMID:Chronic hyponatremia impairs memory in rats: effects of vasopressin antagonist tolvaptan. 2039 12

Vasopressin plays a central role in regulating body fluid homeostasis, serum osmolality and vascular tone. In response to elevated serum osmolality, vasopressin acts on V2 renal receptors increasing water reabsorption and causing serum sodium to decrease. Pathological conditions characterized by abnormally elevated vasopressin levels such as heart failure (HF) or syndrome of inappropriate antidiuretic hormone (SIADH) can result in hyponatremia. Tolvaptan is a new selective nonpeptide vasopressin V2 receptor antagonist that has shown to rapidly normalize serum sodium concentrations in hyponatremic patients. In patients with congestive heart failure (CHF) and symptoms of volume overload, tolvaptan prompted rapid free water elimination and improved short-term signs and symptoms of HF, although no effect on long-term mortality or HF-related morbidity was observed. Data from phase III studies including over 5,000 patients have demonstrated that tolvaptan is a safe and well tolerated vasopressin receptor antagonist, whose long-term use is not associated with adverse outcomes. Tolvaptan has been recently approved for the treatment of hyponatremia and a marketing authorization application has been filed for the treatment of CHF.
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PMID:Tolvaptan for the treatment of hyponatremia and congestive heart failure. 2046 90

Hyponatremia is encountered quite frequently in everyday clinical practice. The symptomatology mainly includes neurological manifestations. In addition, it has been noted in recent years that uncertain gait, falls, fractures, and osteoporosis are also associated with hyponatremia. Based on clinical and laboratory analyses, hyponatremia can be classified into three categories: hypovolemic (decreased volume), hypervolemic (with venous edema), and euvolemic. The severity of the neurological symptoms related to hyponatremia should serve to guide the therapeutic approach. Severe cerebral symptoms due to acute cerebral edema require a prompt and closely monitored course of action with administration of hypertonic saline solution. Milder and moderate symptoms as well as the syndrome of inappropriate ADH secretion (SIADH) can now also be managed with controlled use of the ADH antagonist tolvaptan, one of a new class of vaptans. Tolvaptan is a selective antagonist of the antidiuretic effect of vasopressin without primarily affecting blood pressure and depending on the dose leads to increased excretion of free water (aquaresis). Side effects predominantly concern thirst, polyuria, and hypernatremia. Under these conditions, vaptans represent a valuable asset to the therapeutic spectrum in SIADH. Further studies are needed to determine whether falls and fractures can also be beneficially influenced.
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PMID:[Treatment of hyponatremia: role of vaptans]. 2110 20

The cornerstone of treatment for syndrome of inappropriate antidiuretic hormone secretion (SIADH) is fluid restriction. Demeclocycline is sometimes used but its efficacy is based solely on laboratory endpoints. This drug also has the adverse effects shared by all tetracyclines. Tolvaptan antagonises receptors for arginine vasopressin, a hormone that regulates blood sodium levels by stimulating renal water resabsorption. Tolvaptan is now authorised in the European Union for the treatment of hyponatraemia due to SIADH. Clinical evaluation of tolvaptan in this setting is based on two comparative double-blind placebo-controlled trials including a total of 448 patients with SIADH or hyponatraemia from various other causes. The two trials were combined for analysis. However, because of major methodological flaws, no firm conclusions can be drawn concerning the efficacy in SIADH patients. It remains to be shown that tolvaptan improves symptoms of hyponatraemia (especially neuropsychiatric disorders) or even that it corrects hyponatraemia in these patients. The adverse effects observed in clinical trials were predictable, given the mechanism of action, and included thirst and dry mouth (respectively 16% and 8.4% of patients), hypernatraemia (1.7%), pollakiuria and polyuria. Tolvaptan is metabolised by the cytochrome P450 isoenzyme CYP 3A4, hence a high risk of pharmacokinetic interactions. In summary, there is no reason to use tolvaptan to treat the syndrome of inappropriate antidiuretic hormone secretion: its efficacy on symptoms or even on sodium levels has not been demonstrated, and its adverse effect profile is poorly documented. It is better to concentrate on non-drug management.
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PMID:Tolvaptan: any evidence of efficacy in SIADH? 2118 Mar 68

Arginine vasopressin (AVP) is increased in patients with heart failure (HF). Its actions are linked to free water reabsorption (V2-) and arteriolar vasoconstriction (V1a receptor). AVP can exacerbate the cardiorenal syndrome with excess fluid retention and afterload increase. Tolvaptan (TOL; selective V2 antagonist) and Conivaptan (CON; dual V1a/V2 antagonist) are two AVP antagonists that counteract the action of AVP with distinct profiles. We investigated the therapeutic effects of CON and TOL in an acute HF model. Mongrel dogs were paced continuously at 220 beats/min. After 14 days, the animals underwent acute testing. Dogs were instrumented to measure cardiac output, blood pressure, pulmonary artery pressure, and left ventricular dP/dtmax. Additionally, during the acute experiments, vasopressin was infused intravenously (4 mU/kg/min) to achieve constant and controlled pathophysiological levels of AVP. Subsequently, animals received either CON or TOL (n = 6; 0.1-mg/kg bolus). There were no significant differences in effect on mean arterial pressure, dP/dtmax, central venous pressure, and urine output between CON and TOL. In contrast, cardiac output increased by 0.15 l/min after CON and decreased by 0.6 l/min after TOL (P < 0.01). Accordingly, the total peripheral resistance increased after TOL by 250 dyn*s/cm and decreased after CON by 125 dyn*s/cm (P < 0.01). In conclusion, it was demonstrated that in an acute HF model, CON lowered, whereas TOL increased afterload. The results suggest that dual V1a/V2 blockade in the acute HF setting could be beneficial compared with selective V2 blockade. Chronic experiments are needed to determine whether this finding can translate into a sustained clinical advantage.
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PMID:Differentiation of arginine vasopressin antagonistic effects by selective V2 versus dual V2/V1a receptor blockade in a preclinical heart failure model. 2119 48


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